There are a couple of issues with your question.
- You're asking a very broad question and it would require a book... or dozens of books... to really answer. If you're honestly interested in abstract art, I encourage you to study it a bit. There's such a wide variety of what's considered "abstract" that there's no possible way to have one set of "rules".
Do a Google Image search for "abstract art"... or even look at the Wikipedia page I linked above... when I do, nothing like your sample images even comes up, particularly the first image with the birds and flowers, so perhaps you need a different or more specific term?
Perhaps ask for help defining what type of art your images are so that you can find books that discuss it.
- You're also asking an opinion-heavy question.
I want to understand when do random/abstract shapes look attractive.
You want to know what the rules are to make something "attractive". Personally, I don't generally find abstract art attractive or compelling.
Guernica is one of Picasso's most famous pieces and I think it's sorta ugly.
Avoid asking questions that are subjective or based on personal preference.